Easy to connect 900MHz wireless stereo headphones transmits audio signal through walls, floors, and ceilings, and is compatible with almost any audio source, such as DVD, CD, DBS or HDTV from 150 feet to the transmitter. PLL technology locks in frequency to prevent signal loss. The headphone has a 40 millimeter driver for optimum sound. Ideal for the dorm room, or at home indoors and outdoors.